Currently when creating a Date/Time Picker object by using the time in milliseconds since 01.01.1970 UTC the Date/Time Picker works perfect.
When trying to submit a form containing a Date/Time Picker, the widget will submit the formatted time/date instead of the milliseconds since 01.01.1970 UTC.
There is a workaround to extend the onChange Event and manipulate the value of the input field manually. This might solve the technical problem but now the UTC milliseconds will be displayed inside the widget.
Might it be possible that the widget formats the display date/time and keeps a hidden input field for storing the value? It is actually not possbile to use dates/times in UTC milliseconds with this widget allthough the JavaScript Date object can handle it.